1. Field of the Invention
This invention relates to a tool for installing a protective corner strip along a corner formed by two intersecting wall panels of, for example, sheetrock or gypsum board. More specifically, this invention relates to a hand held power actuated tool usable for attaching a protective corner strip to wall corners of differing contour.
2. Description of the Prior Art
The outside corners of sheetrock or gypsum board walls are customarily finished by attaching a metal strip having a shape which complements the contour of such corners. After the strip is attached to the wall it is covered with joint compound which, after hardening, substantially conceals the protective strip.
The metal strip is sometimes attached to the wall by nailing, however, it is more often attached by forming several indentations or crimps in the side portions of the strip which project into the wall material. Heretofore, the indentations and corresponding projections have been formed using a tool which, when struck with a hammer, simultaneously drives a pair of chisel shaped crimping elements into the opposite sides of the metal strip. The tool is manufactured by the Goldblat Tool Company, Cincinnati, Ohio.
To operate such a tool, a workman must simultaneously manipulate the metal strip, the crimping tool and a hand-held hammer. That is, the workman must with one hand hold the strip in alignment with the corner of the wall and, with the same hand, hold the crimping tool in alignment with the metal strip. When the strip is in alignment with the wall and the tool is aligned with the strip, the workman uses his free hand to strike the tool with the hammer to simultaneously drive the crimping elements into either side of the strip thus attaching the strip to the wall. The workman must be careful to avoid damaging the wall and must strike the crimping tool squarely to avoid breaking metal particles off of the tool which might cause injury. In fact, a warning label attached to the tool expressly cautions of the danger posed by such particles.
In addition to the problems just noted, the Goldblat device is useful only for attaching a protective strip having a shape which complements a right angle-outside wall corner. This presents a serious disadvantage since outside wall corners are commonly formed at angles other than 90.degree. or with rounded contours.
In co-pending application Ser. No. 423,950, filed Oct. 19, 1989, and assigned to the same assignee as the present application, an improved tool which overcomes many of the aforesaid problems is disclosed. More specifically, various embodiments of a power actuated tool usable for attaching a protective strip to wall corners of differing contour is proposed, which substantially reduces the manipulations required with the hand tool and the possibility of industrial accidents. Further, no extraneous implements such as a hammer is required to strike the tool, as the force to do so is self-contained within the tool, and corners near ceilings and adjacent floors may be installed since extraneous striking implements need not be swung in an arc to obtain an effective force applied to the attaching means or crimping elements.
The protective strips are also provided in a number of differing shapes, each one of which complements the contour of the corner to which it is attached. The power tool comprises a shoe releasably mounted on the tool for holding the protective strip and the tool in alignment along the corner. The shoe is provided in a number of differing shapes, each one of which has a contour substantially complementing the contour of an associated protective strip. Since the shoe is releasably mounted on the tool, a shoe having the desired contour is selected from a number of interchangeable shoes of differing shape and mounted on the device to complement the contour of the particular strip being attached.
The power tool further comprises means for releasably mounting the shoe and attaching means comprising crimping elements supported on the shoe for movement between an inactive position wherein the attaching means are out of engagement with the protective strip held by the shoe and an attaching position wherein the attaching means engage and attach the protective strip into holding engagement with the wall panels. Operating means for moving the attaching means from the inactive to the attaching position, biasing means for normally maintaining the attaching means in the inactive position, and power operated means mounted on the shoe and operably connected to the operating means for activating the operating means to move the attaching means to the attaching position are also provided.